Sufficient? What else would you say? Would you go in to detail about all the harassments? I've logged everything from the first day it started. I mean banging our floors, coming upstairs to confront us, calling management, sending security. I'm guessing that she wants to put the complaints in to management so that its on file with them? What's my options and who do I call if something comes out of this after sending the letter?

Once you get the receipt back showing they have gotten the letter, and if she continues to harass, then you will need to go to the Magistrate in your local Court in your county and ask to file a Statement of Charges for harassment. You make the complaint and in the statement you can list all the things the neighbor has done prior to getting your letter, the date the letter was received by them and then the dates and times of the incidents as they continued after being placed on Notice.